Mammoth task, mate, but I'm sure you'll triumph!! I once had a bike in so many bits, but unfortunately my mate had just ploughed it into a driving school car!!!!!

@BSAPowerSet

9 ай бұрын

Yea we'll get there Phil and I feel as though we're on top of it now. At least we've not been having to deal with accident damaged disassembly, unlike yourself, which can be a nightmare. Why do driving school cars seem to attract such carnage?

Hi; regarding use a copper gasket; those are the responsible to erode the center of the heads so the factory changed for the klinger ones. Also the composites are 0.070 (copper are 0.045). Copper gaskets do not let you stranded like the composites but erodes the head between the chambers. The only way (long term use riders) is to re torque head every oil change service. --If you only removed 0.010 you would be good regarding head crush

@BSAPowerSet

Ай бұрын

Thanks for the interest and comment and for your technical notes. I didn’t skim the head - I only ground it so I doubt I had to remove as much as 10 thou. I didn’t realise the composites are thicker than copper; however I’m not a fan of them. In any event my whole ethos is to build the bikes as close to standard as possible. Thanks again.

Novel way of grinding the head gasket face I've only ever seen plate glass fixed on to a bench then the head is ground on top of the glass. Even after washing, can I see grinding paste in the bolt holes ? Good progress on the rebuild looking forward to the chassis rebuild ,don't forget to grease the swing arm bushs/bearings...

@BSAPowerSet

9 ай бұрын

Cheers Matt. Yes I’ve always ground with glass on top of head - less chance of breaking the glass I think and easier to regulate pressure. You’re right there was still grinding paste in the bolt holes so I have cleaned that out. Nearly time for building - at last.

Sometimes, that kind of bowing of the head can be caused by installing the early type pushrod tubes with too great a thickness of seals (it looked like at least one the tubes you took off was the early type). Your replacement tubes are the later type, which should not suffer from that issue.

@BSAPowerSet

9 ай бұрын

Thanks Rick. I hadn't thought about that and wasn't aware of earlier/later types, but you're right - the pushrod tubes are not a matching pair so hopefully that risk in the future will be mitigated by the new tubes. Thanks again.

Thanks for the videos. They've been helpful. I picked up a 78 T140 recently that needs some love. I'm going to pull the rocker boxes and head off to replace a leaky push rod seal on the intake side. If I wanted to throw the entire head into the ultrasonic cleaner with the valves and springs still in place (I have no need to remove those at this point in time) would that be okay? It doesn't seem like it would hurt anything as long as I dry it off properly, but I'm new to this stuff. My plan is to leave the cylinder barrels in place, just pull off enough to get the new pushrod seals in there. Bike runs fine at the moment. I'm tempted to pull the cylinder barrels off and put a new gasket on while I have the other stuff off. Everything else will be getting fresh gaskets before going back together.

@BSAPowerSet

6 ай бұрын

Glad they’ve been helpful. You could put the valves and springs in the cleaner in place and they should be ok - perhaps with a littl surface rust in drying afterwards - but If you’re removing the head then it’s not really much of a job to remove the valves and springs to check the seats and also the valve guide wear at the same time.

Hello; what kind of detergent? the dishwasher one? what about to clean the carburetors? I used an special product from Wurth diluted in water because I thought that detergent etc would not remove old particles and old gasoline trapped in the pilot jets etc but I am not sure. Thanks

@BSAPowerSet

Ай бұрын

I use a proprietary water based detergent solution especially for ultrasonic cleaners. I run the cleaner at 60C. It cleans alloy and carbs very well. I don’t know what chemicals are in the solution but believe it is alkaline. Some people use specialist carb cleaner but you have to be very careful with any aromatic solvent based solutions especially at the temp I use. Thanks again for the interest.

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